title: Integration of microwave tomography with magnetic resonance for improved breast imaging.
abstract: OBJECTIVE
  Breast magnetic resonance imaging is highly sensitive but not very specific for the detection of breast cancer. Opportunities exist to supplement the image acquisition with a more specific modality provided the technical challenges of meeting space limitations inside the bore, restricted breast access, and electromagnetic compatibility requirements can be overcome. Magnetic resonance (MR) and microwave tomography (MT) are complementary and synergistic because the high resolution of MR is used to encode spatial priors on breast geometry and internal parenchymal features that have distinct electrical properties (i.e., fat vs fibroglandular tissue) for microwave tomography.
  
  
  METHODS
  The authors have overcome integration challenges associated with combining MT with MR to produce a new coregistered, multimodality breast imaging platform--magnetic resonance microwave tomography, including: substantial illumination tank size reduction specific to the confined MR bore diameter, minimization of metal content and composition, reduction of metal artifacts in the MR images, and suppression of unwanted MT multipath signals.
  
  
  RESULTS
  MR SNR exceeding 40 dB can be obtained. Proper filtering of MR signals reduces MT data degradation allowing MT SNR of 20 dB to be obtained, which is sufficient for image reconstruction. When MR spatial priors are incorporated into the recovery of MT property estimates, the errors between the recovered versus actual dielectric properties approach 5%.
  
  
  CONCLUSIONS
  The phantom and human subject exams presented here are the first demonstration of combining MT with MR to improve the accuracy of the reconstructed MT images.
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Meaney
authors.forename: Amir H
authors.initials: AH
authors.lastname: Golnabi
authors.forename: Neil R
authors.initials: NR
authors.lastname: Epstein
authors.forename: Shireen D
authors.initials: SD
authors.lastname: Geimer
authors.forename: Margaret W
authors.initials: MW
authors.lastname: Fanning
authors.forename: John B
authors.initials: JB
authors.lastname: Weaver
authors.forename: Keith D
authors.initials: KD
authors.lastname: Paulsen
mesh_terms: D000328:Adult; D016477:Artifacts; D001940:Breast; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008872:Microwaves; D019047:Phantoms, Imaging; D018511:Systems Integration; D014054:Tomography / Q000379:methods*